Hoist operating hand wheel incorporating an overload protection mechanism

ABSTRACT

A hoist operating hand wheel including concentric hub and rim portions; the hub portion pivotally supporting three dog-leg shaped arms carrying rollers normally biased by adjustable tension springs into engagement with roller receiving recesses formed in a radially inwardly facing surface of the rim portion. When an attempt is made to raise a load in excess of desired hoist capacity, the rollers are forced to ride out of their associated recesses against the return bias of the tension springs, thereby permitting rotation of the rim portion relative to the hub portion. A single removable cover plate carried by the hub portion affords access for adjusting the tension springs and normally retains the arms and rim portion in assembled position on the hub portion.

ilnited States Patent [191 Hawkins et al.

1111 3,724,815 1 Apr. 3, 1973 both of Williamsville; Alfred M. Parslow,Tonawanda, all of N.Y.

[73] Assignee: Columbus KcKinnon Corporation,

Tonawanda, N.Y. Y

221 Filed: ,lune 3,1971

[21] Appl. No.: 149,705

[52] US. Cl ..254/169, 64/29 [51] Int. Cl. ..B66d 1/00 {58] Field ofSearch .254/169, 150, 172; 64/29, 64/27 CS [56] References Cited UNITEDSTATES PATENTS 1,443,026 1/1923 Lee ..64/29 1,634,912 7/1927 Miller..254/172 4/1944 Clarke ..254/172 11/1970 Stevens PrimaryExaminer-Harvey C. Hornsby Attorney-Bean & Bean [57] ABSTRACT A hoistoperating hand wheel including concentric hub and rim portions; the hubportion pivotally supporting three dog-leg shaped arms carrying rollersnormally biased by adjustable tension springs into engagement withroller receiving recesses formed in a radially inwardly facing surfaceof the rim portion. When an attempt is made to raise a load in excess ofdesired hoist capacity, the rollers are forced to ride out of theirassociated recesses against the return bias of the tension springs,thereby permitting rotation of the rim portion relative to the hubportion. A single removable cover plate carried by the hub portionaffords access for adjusting the tension springs and normally retainsthe arms and rim portion in assembled position on the hub portion.

5 Claims, 2 Drawing Figures I-IOIST OPERATING HAND WHEEL INCORPORATINGAN OVERLOAI) PROTECTION MECHANISM SUMMARY OF THE INVENTION The presentinvention relates to a novel hand wheel construction, and moreparticularly to improvements in hand wheels of the general typedisclosed by U.S. Pat. No. 3,542,341, wherein a hoist overloadprotection mechanism is incorporated within the hand wheel.

The hand wheel construction of the present invention features a hubportion, which is adapted to be drivingly interconnected to a loadlifting wheel of a hoist to be protected against overloading, and a rimportion, which is journaled on the hub portion and drivingly engageableby a manually operated hoist operating chain.

The hub and rim portions cooperate to define an annularly shaped axiallyopening recess in which a plurality of arms are journaled intermediatethe ends thereon on hub portion carrier pin shafts for pivotal movementsabout axes arranged essentially parallel to the axis of hand wheelrotation. A roller is mounted adjacent one end of each of the arms forrotation about an axis parallel to the pivot axis of its associated arm;such roller being normally biased radially outwardly for couplingengagement within roller receiving recesses formed in a radiallyinwardly facing or cavity bounding surface of the rim portion by meansof a tension spring fixed to another end of its associated arm.

When a load connected to the load lifting wheel of the hoist is inexcess of desired hoist load capacity, any attempt to-manipulate the rimportion for the purpose of lifting such load overcomes the coupling biasafforded by the tension springs, thereby resulting in the rollers beingforced to roll out of their associated recesses so as to permit relativerotation between the rim and hub portions. Preferably, the rear surfacesof the recesses are sharply inclined such as to minimize relativemovement between the rim and hub portions until the rollers have beencompletely forced out of the recesses in which they are initiallydisposed, whereas the front surfaces of the recesses are relativelygradually inclined to permit the rollers to smoothly ride into anadjacent recess, thereby to cushion the resulting shock.

Preferably, each tension spring is a coil spring fixed to the hubportion by means of an anchor device including a pin arrangedeccentrically on a base portion adapted to be screw threaded into thehub portion, the eccentricity of the pin and its threaded basepermitting adjustments of spring tension, as required.

In a preferred construction, the rim portion and arms are removablyretained in assembled condition on the hub portion by means of a hubportion mounted ringshaped cover, which additionally serves to seal andprevent admission of dirt or the like into the cavity.

The present invention provides a simply constructed, inexpensive handwheel, which is capable of being readily adjusted to insure accurateoverload release control.

DRAWINGS The nature and mode of operation of the present invention willnow be more fully described in the following detailed description takenwith the accompanying drawings wherein:

FIG. 1 is a front elevational view of the hand wheel of the presentinvention having its front plate removed for purposes of clarity; and

FIG. 2 is a sectional view taken generally along the line 22 in FIG. 1.

DETAILED DESCRIPTION Now referring more particularly to the drawings, 10is employed to generally designate the hand wheel of the presentinvention, which is characterized as having a rim portion 12 and a hubportion 14. As is conventional in hand wheel operated hoistconstructions, hub portion 14 is provided with an axially extending orcentered screw-threaded opening 16 for reception of the usual screw 18formed as a part of a Weston type brake 20. Hand wheel 10 may beremovably retained on its associated hoist by suitable means, such asnut 21.

When hand wheel 10 is rotated in the direction indicated in FIG. 1 byarrow 22, such as by a downward pull on a manually manipulated linkchain 24 trained about a rim portion 12, Weston brake 20 is operable todrivingly connect the hand wheel to a load lifting wheel, not'shown, forthe purpose of lifting a load, also not shown. Of course, when chain 24is manipulated to rotate wheel 10 in an opposite direction, Weston brake20 permits controlled lowering of a load carried by the hoist. Hoistconstructions employing Weston or like brakes are well known, and thus,no detailed discussion thereof is deemed necessary.

In FIG. 2, rim portion 12 is shown as being formed from a pair of rimsections 12a and 12b, which are joined in abutting relation by asuitable means, such as a plurality of rivet devices 26, and hub portion14 is shown as being formed as a one-piece metal casting. Preferably,rim sections 12a and 12b are formed in accordance with the disclosure ofUS. Pat. No. 2,535,985, whereby they are formed with spaced partitionelements 28a and 28b, which cooperate to define pockets foraccommodating the links of chain 24. Section 12b and thus rim portion 12are journaled for rotation concentrically of hub portion 14 by asuitable bearing device, such as an annularly extending sleeve 30 ofL-shaped cross-section engageable by facing peripheral surfaces of boththe hub and section 12b. As best shown in FIG. 2, rim section 12b isformed with an axially extending annular flange or sleeve portion 32,which cooperates with hub portion 14 to define an annular, axiallyopening cavity 34; cavity 34 being sealed or closed to dirt or the likeby a ring-shaped cover member 36, which is fitted within flange portionannular groove 38 and removably fixed to hub portion 14 by threadedfasteners 40. Preferably, dowel pins 42 are fixed to hub portion 14 inorder to insure proper orientation of cover member 36 relative to thehub portion prior to insertion of threaded fasteners 40. By formingcover member 36 in the form of a ring, ready access is afforded to nut21 for purpose of removably mounting hand wheel 10 on screw shaft 18.

As best shown in FIG. 1, the radially inner surface of flange portion 32is shaped to define a plurality of radially inwardly opening recesses44. For the reasons to be hereinafter discussed, recesses 44 arepreferably formed with gradually sloping and smoothly contoured frontwall surfaces 44a and sharply sloping rear wall surfaces 44b, whenconsidered relative to the load'lifting direction of hand wheelrotation.

Reference is again made particularly to FIG. 1, wherein hub portion 14is shown as being of releasably connected or coupled for driven rotationwith rim portion 12 by three identical overload devices, which aregenerally designated as 50 and arranged in an equally spacedrelationship circumferentially of hub portion 14. Devices 50 includedog-leg shaped arm members 52, which are journaled intermediate theirrespective ends on hub portion fixed pin shafts 54 for radial pivotalmovements about essentially parallel axes 56. Axes 56 are in turnarranged essentially parallel to the axis ofrotation of hand wheel 10,which is designated at C.L. in FIG. 2. A roller 58 is journaled,vas by apin shaft 60, adjacent one bifurcated end of each of arm members 52 forrotation about an axis arranged essentially parallel to axes 56. Each ofrollers 58 are normally biased outwardly for engagement within one ofrecesses 44 by means of a coil type tension spring 62, which is mountedon hub portion 14 by an anchor device 64 and fixed to an oppositebifurcated end of an associated arm member by means of pin shaft 66. Forpurposes of mechanical advantage, the distance between pin shafts 54 and66 is made greater than that between pin shaft 54 and 60. I

in a preferred form of the presentinvention, each of anchor devices 64includes a pin, shaft 68, which is annularly slotted to receive a hookedend portion of an associated tension spring 62, and a base portion 70,which is arranged eccentrically of pin shaft 68 and adapted to be screwthreaded into hub portion 14.'By this arrangement, the tension ofsprings 62 may be individually adjusted by anamount corresponding to thedisplacement of pin shaft 68 as a' result of a 180 rotation of baseportion 70. Of course, if desired, other means may be employed to anchorsprings 62 to hub portion 14.

Again referring to FIG. 2, it will be seen that cover member 36, inaddition to providing a dirt seal for cavity 34, normally serves toretain rim portion 12 in position on bearing 30; to retain arm members52 journaled on pin shafts 54; and to prevent accidental adjustments ofanchor device 64, due to'engagement thereof with objects during use ofthe hoist. This construction provides for simplicity in construction andease of assembly, as well as permitting adjustment of the tensionsprings withoutrequiring the handwheel to be disassembled or removedfrom a hoist.

From the foregoing it will be understood that the maximum load which maybe lifted by a hoist with which hand wheel.,l is associated, isdetermined by the number of tension springs employed, their springcharacteristics and/or by adjustments of such springs by anchor devices64. Normally, it is preferable to employ springspermitting overloadrelease at a load substantially below that load at .which structuraldamage to the hoistand/or a load lifting chain might occur. Thus, when aload connected to the load lifting wheel of the hoist is in excess of adesired hoist capacity, any attempt to rotate rim portion 12 for thepurpose of lifting such load overcomes the coupling bias afforded bytension springs 62, thereby resulting in rollers 58 being forced to rideout of their associated recesses 44- and permitting subsequent rotationof rim portion 12 relative to hub portion 14. Relative rotation of rimportion 12 together with the noise produced by rollers moving intosuccessive recesses serves as a clear warning to the hoist operator, aswell as others in the area, that an overload condition exists.

By sharply sloping rear wall surfaces 44b of the recesses, relativelyinsignificant relative rotation of the rim and hub portions is permitteduntil the overload condition is reached; this being desirable from thestandpoint that no 37 slack or looseness is sensed by the operatormanipulatingchain 24 during normal hoist lifting operation. Therelatively slight slope provided for front wall surfaces 440 permits therollers to smoothly ride into the recesses, thereby to minimize joltingand resulting shocks.

The specific construction of hand wheel 10, as hereinabove described,has been found particularly suitable for use with one and two tonhoists. As will be apparent, the basic construction may, however, bereadily modified, as desired, for exampleby varying the number ofoverload devices or the type of springs employed.

We claim:

1. A hand wheelhaving utility in preventing overloading of a loadlifting hoist of the type having a drive connection for rotatablysupporting the hand wheel, said hand wheel comprising in combination:

a hub portion adapted to be supported by said hoist drive connection forrotation about an axis;

a rim portion for driving said hub portion for rotation about said axisin opposite hoist-loadlifting and hoist load lowering directions;

bearing means engageable by facing peripheral surfaces of both said rimand hub portions for journaling said rim portion on said hub portion forrotation concentrically outwardly thereof while permitting disassemblyof said rim portion from said hub portion upon movement of the former,in a direction axially away from saidhoist drive connection, saidrimportion having an annular flange portion disposed concentrically of saidaxis and extending in said direction away from said bearing means, saidflange portion and said hubportion cooperating to define a cavityopening axially to I one side ofsaid hub portion in said direction, andsaid flange portion 7 defining radially v inwardly opening recessesspaced circumferentially of said cavity; I

at least one arm member;

means forsu'pportin'g said arm member on said hub portion within saidcavity for pivotal movement about a pivot axis arranged parallel to saidaxis;

a roller carried on said arm member for rotation about an axis arrangedparallel to the pivotaxis thereof;

spring means for resiliently biasing said arm member to .pivot about'itspivot axis in a first direction thereby to normally yieldably maintainsaid roller in one of said recesses for releasably connecting said hubportion to said rim portion for drive rotations therewith; I

a cover member for closing said cavity and releasably maintaining saidrim portion assembled on said hub portion; and means for removablyfixing said cover member to said hub portion adjacent. said one side toextend radially of said axis into engagement with said flange portion,whereby to releasably maintain said rim portion assembled on said hubportion in association with said bearing means.

2. A hand wheel according to claim 1, wherein said means for supportingsaid arm member includes a pin shaft, and said cover member additionallyserves when fixed to said hub portion to releasably retain said armmember on said pin shaft.

3. A hand wheel according to claim 1, wherein said hand wheeladditionally includes adjustment means for adjusting said spring meansto vary the bias thereof, and said spring means is a tension springhaving opposite ends thereof connected one to each of said springadjustment means and said arm, said spring adjustment means including ascrew portion threadably received within said hub portion for rotationabout an axis essentially parallel to said pivot axis and a spring endattaching portion mounted eccentrically of said screw portion, wherebyupon rotation of said screw portion said attaching portion is movedalong a path to vary the tension of said spring.

4. A hand wheel according to claim 1, wherein said hub portion is formedwith an opening to accommodate said hoist drive connection to extendaxially therethrough, whereby affording access for removably mountingsaid hub portion on said hoist drive connection from adjacent said oneside of said hub portion, said cavity is of an annular configuration,and said cover member is of ring shaped configuration fixed to said hubportion concentrically outwardly of said opening thereof.

5. A hand wheel according to claim 4, wherein said means for supportingsaid arm member includes a pin shaft, and said cover member additionallyserves when fixed to said hub portion to releasably retain said armmember on said pin shaft and wherein aid hand wheel additionallyincludes adjustment means for adjusting

1. A hand wheel having utility in preventing overloading of a loadlifting hoist of the type having a drive connection for rotatablysupporting the hand wheel, said hand wheel comprising in combination: ahub portion adapted to be supported by said hoist drive connection forrotation about an axis; a rim portion for driving said hub portion forrotation about said axis in opposite hoist load lifting and hoist loadlowering directions; bearing means engageable by facing peripheralsurfaces of both said rim and hub portions for journaling said rimportion on said hub portion for rotation concentrically outwardlythereof while permitting disassembly of said rim portion from said hubportion upon movement of the former in a direction axially away fromsaid hoist drive connection, said rim portion having an annular flangeportion disposed concentrically of said axis and extending in saiddirection away from said bearing means, said flange portion and said hubportion cooperating to define a cavity opening axially to one side ofsaid hub portion in said direction, and said flange portion definingradially inwardly opening recesses spaced circumferentially of saidcavity; at least one arm member; means for supporting said arm member onsaid hub portion within said cavity for pivotal movement about a pivotaxis arranged parallel to said axis; a roller carried on said arm memberfor rotation about an axis arranged parallel to the pivot axis thereof;spring means for resiliently biasing said arm member to pivot about itspivot axis in a first direction thereby to normally yieldably maintainsaid roller in one of said recesses for releasably connecting said hubportion to said rim portion for driven rotations therewith; a covermember for closing said cavity and releasably maintaining said rimportion assembled on said hub portion; and means for removably fixingsaid cover member to said hub portion adjacent said one side to extendradially of said axis into engagement with said flange portion, wherebyto releasably maintain said rim portion assembled on said hub portion inassociation with said bearing means.
 2. A hand wheel according to claim1, wherein said means for supporting said arm member includes a pinshaft, and said cover member additionally serves when fixed to said hubportion to releasably retain said arm member on said pin shaft.
 3. Ahand wheel according to claim 1, wherein said hand wheel additionallyincludes adjustment means for adjusting said spring means to vary thebias thereof, and said spring means is a tension spring having oppositeends thereof connected one to each of said spring adjustment means andsaid arm, said spring adjustment means including a screw portionthreadably received within said hub portion for rotation about an axisessentially parallel to said pivot axis and a spring end attachingportion mounted eccentrically of said screw portion, whereby uponrotation of said screw portion said attaching portion is moved along apath to vary the tension of said spring.
 4. A hand wheel according toclaim 1, wherein said hub portion is formed with an opening toaccommodate said hoist drive connection to extend axially therethrough,whereby affording access for removably mounting said hub portion on saidhoist drive connection from adjacent said one side of said hub portion,said cavity is of an annular configuration, and said cover member is ofring shaped configuration fixed to said hub portion concentricallyoutwardly of said opening thereof.
 5. A hand wheel according to claim 4,wherein said means for supporting said aRm member includes a pin shaft,and said cover member additionally serves when fixed to said hub portionto releasably retain said arm member on said pin shaft and wherein aidhand wheel additionally includes adjustment means for adjusting saidspring means to vary the bias thereof, and said spring means is atension spring having opposite ends thereof connected one to each ofsaid spring adjustment means and said arm, said spring adjustment meansincluding a screw portion threadably received within said hub portionfor rotation about an axis essentially parallel to said pivot axis and aspring end attaching portion mounted eccentrically of said screwportion, whereby upon rotation of said screw portion said attachingportion is moved along a path to vary the tension of said spring.